Figure 1.

Proposal: The olfactory system uses two kinds of disorder to first compress odor information into the responses of a small number of receptors, and then reconfigure this information to enable flexible associations between odors and valences. (i) Natural odors are high dimensional but sparse: they contain a tiny fraction of all possible monomolecular odorants. (ii) Olfactory receptors diffusely bind to a broad range of odorants, producing a compact representation of odor information that enables accurate decoding. (iii) The Antennal Lobe/Olfactory Bulb decorrelates this representation. (iv) Disordered projections from the Antennal Lobe/Olfactory Bulb to the Mushroom Body/Piriform Cortex, followed by non-linearities, create a sparse and distributed representation of odors that facilitates flexible learning of odor categories from small and arbitrarily-chosen subsets of neurons.